Near Field RF Communicator Impedance Sensing for Power Reduction
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Solution Overview
Problem
Near field RF communicators face power consumption issues when initiating communication, as they need to transmit an RF signal to wake up responding devices, which consumes time and power, and this can lead to failures in applications where battery replacement or recharging is not possible.
Innovation Solution
A near field RF communicator that senses the presence of a target device by generating a sense signal with short bursts or reduced amplitude, detecting changes in impedance or phase relationships, and only initiates communication when a target is confirmed in range, thereby reducing unnecessary power drain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the near field RF communicator transmits an RF signal to wake up the responding device, then communication can be initiated, but power consumption increases and battery life decreases
Solution Approach 1:
The patent applies preliminary action by first transmitting a low-power sense signal to detect the presence of a target device before committing to a full communication initiation. The controller monitors impedance changes caused by the sense signal to confirm target presence, ensuring that the higher-power activation signal is only transmitted when necessary, thus reducing overall power consumption while maintaining reliable communication initiation.
2Reliability
If the near field RF communicator transmits an RF signal to wake up the responding device, then communication can be initiated, but time is consumed in the wake-up process
Solution Approach 1:
The patent segments the communication initiation process into two distinct phases: a detection phase using low-power sense signals to identify target presence through impedance monitoring, and an activation phase using higher-power signals only when a target is confirmed. This segmentation eliminates unnecessary full-power transmission attempts, reducing the overall time required for successful communication initiation.
3Speed
If the near field RF communicator continuously monitors for targets, then response time is reduced, but power consumption increases
Solution Approach 1:
The patent implements periodic action by having the controller transmit sense signals at specific intervals rather than continuously monitoring. The system periodically scans for targets using low-power sense signals, monitors impedance changes to detect presence, and only activates full communication when a target is detected. This periodic approach maintains responsive detection capability while significantly reducing power consumption compared to continuous monitoring.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows the near field RF communicator to determine the presence of a target device without fully waking it up, reducing initial power consumption and extending battery life in battery-powered devices.
Implementation Method 1
Near field RF (radio frequency) communication requires an antenna of one near field RF communicator to be present within the alternating magnetic field (H field) generated by the antenna of another near field RF communicator by transmission of an RF signal
Implementation Method 2
a sensor to sense a change in an impedance of the inductive coupler due to inductive coupling of the sense signal between the inductive couplers of the near field RF communicator and another near field RF communicator in near field range
Data Source
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AI summary
A near field RF communicator (100) has an inductive coupler (102) and a first signal provider (109, 110, 111) to cause the inductive coupler to provide a first signal that when inductively coupled to the inductive coupler of another near field RF communicator in near field range is insufficient to cause initiation of communication with that other near field RF communicator. A sensor (116) senses a change in an impedance of the inductive coupler (102) due to inductive coupling of the first signal between the inductive couplers of the said near field RF communicator and a said other near field RF communicator in near field range. A controller (107) determines whether or not another near field RF communicator is in near field range on the basis of any change in impedance sensed by the sensor and, if another near field RF communicator is determined to be in near field range, causes a second signal to be inductively coupled to the other near field RF communicator to initiate communication between the two near field RF communicators. The sensor may use a phase detector (118) to enable a change in impedance to be sensed by detecting a change in a current-voltage phase relationship resulting from a change in impedance.